Fuels and fuel additives comprising ester derivatives of 5-methyl-2-furoic acid

ABSTRACT

Ester derivatives of furoic acids and in particular of 5-methyl-2-furoic acid can be used as fuel as fuel additives. Such esters can be used to displace crude oil products such as gasoline, diesel, jet fuel, etc. As fuel additives, such esters had been shown to improve the performance of spark ignition internal combustion engines, compression ignition internal combustion engines. In addition, testing shows indications that said molecule will improve the performance of air breathing engines as well.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority as a continuation in part of PCT application PCT/US2013/059836, filed Sep. 14, 2013; and to the following US provisional applications to which said application claimed priority: 61/818,418, filed May 1, 2013, 61/714,225, filed Oct. 1, /2012, and 61/705,082, filed Sep. 24, 2012. This application claims priority as a continuation in part of U.S. application Ser. No. 13/817,452, filed Mar. 5, 2013, and to the following applications to which said application claimed priority: PCT/US2011/048009 filed Aug. 17, 2011; 61/375,189, filed Aug. 19, 2010; and 61/375,367, filed Aug. 20, 2010. Each of the foregoing applications is incorporated herein by reference.

BACKGROUND ART

The present invention concerns the use of molecules of Formula I (as shown in FIG. 1) as fuels and fuels additives, where R is hydrogen, alkyl, or aromatic with 1 to 10 carbon atoms, or combination of carbon, hydrogen, and oxygen and R[sub]1 comprises alkyl or aromatic, with between 1 and 18 carbon atoms, or a combination of carbon, hydrogen, and oxygen.

“Oxygenates” are molecules containing atoms of oxygen, carbon and hydrogen that are used in the fuel and fuel additives field to obtain certain desirable properties in fuel blends. The EPA had mandated the use of oxygenates in gasoline for many years specifically to reduce air pollution, in particular ground-level ozone, carbon monoxide (CO), and smog. (1970 CAA, 1990 CAAA, Energy Independence and Security Act of 2007 (Pub.L. 110-140)). Other performance enhancing properties are also associated with some oxygenates, such as increased octane rating and higher torque/horsepower output.

Methyltertiary butylether (MTBE), for example, was used extensively in gasoline in the US to reduce emissions and increase octane (M. Winterberg, E. Schulte-Korne, U. Peters, F. Nierlich “Methyl Tert-Butyl Ether” in Ullmann's Encyclopedia of Industrial Chemistry, 2010, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_(—)543.pub2). However, the use of MTBE in gasoline had been drastically reduced in later years due to contamination of large amount of groundwater as a result of comparatively small gasoline leaks.

Ethanol had been successfully used in Brazil as both a gasoline oxygenate and a complete fuel replacement, serving as a potential example for self-reliance on domestically produced fuels. However, the use of ethanol is limited to gasoline and even as a blended component in gasoline has some shortfalls. For example, alcohols such as methanol and ethanol tend to absorb water as a result of their polar hydrophilic character. Phase separation is commonly observed in a gasoline-alcohol blend once even a small amount of water is absorbed. This can result in the accelerated corrosion of a fuel system as well as plugging of fuel filters by the corrosion products. Also, increased wear from the fuel wetted components, such as fuel pumps, injectors, etc., is a known phenomenon. Extraordinary precautions must therefore be taken to avoid water contamination of alcohol-containing fuels. (CRC Project CM-136-09-1B, CRC Report No. 664, CRC Report No. E-90, CRC REPORT NO. 662, Renewable Fuels Association: E15 Misfueling Mitigation Plan). Another shortfall of ethanol is its comparatively low energy density, with regard to gasoline, a property that reduces the fuel economy of the vehicle.

Ethanol was tested heavily as a potential candidate to reduce particulate matter in diesel, but was shown to reduce the flash point to a level that renders the blend unusable in diesel engines. Due to its low energy content, the use of ethanol in jet fuel is generally not acceptable by the engine manufacturer. Other oxygenates showed similarly poor performance in both diesel and jet fuels.

DESCRIPTION OF INVENTION

The present invention concerns the use of molecules of Formula I (as shown in FIG. 1) as fuels and fuels additives, where R is hydrogen, alkyl, or aromatic, with 1 to 10 carbon atoms, or combination of carbon, hydrogen, and oxygen and R[sub]1 comprises alkyl or aromatic, with between 1 and 18 carbon atoms, or a combination of carbon, hydrogen, and oxygen. Of particular importance to this invention is the use of molecules of Formula II, where R[sub]1 comprises an alkyl with between 1 and 18 carbon atoms as fuels and fuel additives. Such derivatives had been shown to be made from renewable feedstock by Mikochik and Cahana (PCT/US2011/048009 CA2808842A1, EP2606039A1). Further, the major precursor for such derivatives can be made from cellulosic material on a commercial scale as described by Cahana and Zhang et al. in PCT application PCT/US13/57795, filed 3 Sep. 2013, incorporated herein by reference.

In addition to molecules of Formula I and II as they are described herein being oxygenates, they can also be made to have energy density that is equal to or greater than that of gasoline, diesel and jet fuel. This and other properties allow the use of molecules of Formula I and II as fuels and/or fuel additives. In engine studies conducted with these molecules, it was found that the use of molecules of Formula II in diesel allowed for reduction of about 50% in particulate matter as emitted directly from the engine. Another notable finding that is based in testing is the lubricity properties of molecules of Formula II, which are particularly useful in diesel. In testing, it was found that by replacing 10% by volume of diesel with molecules of Formula II where R[sub]1 is an alkyl with 2 carbon atoms, the lubricity of the mixture was improved by 33%. Such property is important for the life of the engine and the fuel system. Yet another notable finding that is based in testing is that when molecules of Formula II where R[sub]1 is an alkyl with between 1 and 4 carbon atoms are blended with diesel, the cold weather performance of the diesel blend can improve.

The present invention concerns the use of molecules of Formula II as fuels and fuel additives in all types of internal combustion engines, external combustion engines and air-breathing combustion engines. As a fuel, molecules of Formula II can be used to displace crude oil products by providing the energy required for the work generated by the engine. That energy is released when molecules of Formula II are combusted. As a fuel additive, molecules of Formula II can be used as an oxygenate, and to impart desirable properties to the fuel, such as increased combustion efficiency, improve lubricity, improve anti-knock properties, reduce harmful emissions, and/or increasing horsepower and torque.

Testing conducted by independent ISO/IEC laboratories of blends containing molecules of Formula II had shown that these blended molecules of Formula II enhances the properties of both gasoline and diesel. For example, testing conducted by Paragon Laboratories Inc. showed that a 10% blend of a molecule in Formula II where R1 is an ethyl group showed an increase in octane (RON+MON/2) from 91.15 to 92.5. Another test conducted by International Lubrication and Fuel Consultants, Inc. of a similar 10% blend of gasoline and Formula II molecules showed a decrease in Reid vapor pressure from 6.0 psi to 4.0 psi.

Molecules of Formula II can comprise up to 25% by volume of the fuel for spark ignition internal combustion engines (SIICE) with little to no reduction in engine performance. In this case, 75% to 99.99% of the fuel can be composed of typical fuel blends that are used in SIICE, such as those used for transportation, recreation and general work, and which the properties of the mixture are referenced by standards such as ASTM D4814. This fuel is commonly referred to as gasoline. If alcohols such as ethanol comprise some portion of the fuel blend, the volume of molecules of Formula II can be adjusted such that the total oxygen content of the fuel mixture shall not exceed 8.3% by weight. As described in this paragraph, the use of molecules of Formula II can lead to improved performance of the SIICE, such as increase in fuel combustion efficiency. Molecules of Formula II that are particularly useful for this invention include those where R[sub]1 is an alkyl with between 1 and 4 carbon atoms.

Improved fuel combustion efficiency as described above is reflected in measurements of octane rating and/or fuel economy and/or emissions quality. A further advantage of the present invention is that in a mixture comprising of molecules of Formula II and gasoline fuel the Reid vapor pressure of the fuel is not adversely affected. That is, the Reid vapor pressure is desirably lowered. This is a distinct advantage since potentially low cost, highly volatile, fuel components such as butanes can then be blended into the fuel without exceeding the desired vapor pressure limit.

Fuel blends for SIICE can comprise up to 100% of molecules of Formula II with appropriate modifications to the engine and/or fuel systems. For example, a high compression and/or forced induction engine with appropriate fuel pumps and fuel injectors with higher mass flow rate can utilize a fuel comprising up to 100% of molecules of Formula II.

Molecules of Formula II can comprise up to 100% by volume of the fuel for compression ignition internal combustion engines (CIICE) with little to no reduction in engine performance. In this case, 70% to 99.99% of the fuel will be composed of typical fuel blends that are used in CIICE, such as those used for transportation, recreation and general work, and which the properties of the mixture are referenced by standards such as ASTM D975. This fuel is commonly referred to as Diesel. The use of biodiesel (fatty acid methyl esters) in the blend is also possible. The use of molecules of Formula II as described herein also serves to reduce and/or limit particulate matter generation in CIICE engines. The lubricating properties of molecules of Formula II can increase the useable life of the engine itself and/or components within the engine and/or the fuel systems. Molecules of Formula II that are particularly useful for this invention include those where R[sub]1 is an alkyl with between 1 and 12 carbon atoms.

Molecules of Formula II can be used at up to 100% to provide the energy required for the engine to generate work in fuel blends that are typical for use with external combustion engines.

Molecules of Formula II can comprise up to 50% by volume of the fuel for air-breathing combustion engines with little to no reduction in engine performance. In this case, 80% to 99.99% of the fuel can be composed of typical fuel blends that are used in air-breathing engines, such as those used for transportation, recreation and general work, and which the properties of the mixture are referenced by standards such as ASTM D1655 and/or ASTM D7566. This fuel is commonly referred to as Jet Fuel. The use of molecules of Formula II as described herein also serves to reduce and/or limit particulate matter generation in air-breathing engines. The lubricating properties of molecules of Formula II can increase the useable life of the engine itself and/or components within the engine and/or the fuel system. Molecules of Formula II that are particularly useful for this invention include those where R[sub]1 is an alkyl with between 1 and 12 carbon atoms.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form part of the specification, illustrate the present invention and, together with the description, describe the invention. FIG. 1 is a schematic illustration of the structure of molecules of Formula I and Formula II.

MODES FOR CARRYING OUT THE INVENTION AND INDUSTRIAL APPLICABILITY

An example embodiment of the present invention provides a fuel blend comprising from about 6% to about 20% linear paraffins by volume, from about 25% to about 47% branched paraffins by volume, from about 17% to about 50% alkylated benzenes by volume, about 10% ethanol by volume and about 16% by volume of molecules of Formula II where R[sub]1 is an alkyl with between 1 and 2 carbon atoms. Such mixture will contain about 8.3% oxygen by weight, such that no modification to a common SIICE engine is required. As can be seen in this embodiment, crude oil products are displaced at about 26% by volume in favor of renewable fuels.

In this embodiment, the performance of SIICE engines burning this blend of fuels would not be compromised and can be significantly increased due to the higher octane rating and lower stoichiometric air/fuel ratio. Emissions of harmful greenhouse gases such as carbon monoxide, ozone, etc. can be significantly reduced due to the relatively high percentage of oxygen (8.3 wt/wt %) in the fuel.

Another example embodiment of the present invention provides for a gasoline fuel blend comprising 25% of molecules of Formula II where R[sub]1 is either a methyl or ethyl group. In such a blend, the Reid vapor pressure can be reduced while the octane rating can be increased. This allows for the addition of lower cost gasoline components such as butane and linear (straight chain) paraffins. A further advantage of such a blend is a decrease in evaporative emissions of hydrocarbons due to the decrease in Reid vapor pressure and also a decrease in greenhouse gas emissions due to the higher level of oxygen in the fuel itself.

Another example embodiment of the present invention provides for a fuel blend comprising 100% of molecules of Formula II where R[sub]1 is an alkyl with between 1 and 4 carbon atoms. Specially designed engines such as very high compression engines and/or forced induction engines can be required to burn this type of blend, but these engines can also have advantages over typical internal combustion engines. Namely, a higher compression ratio and/or high boost pressure from forced induction increases combustion efficiency and increases the horsepower and torque output of the engine. This can result in smaller engines with larger power output, reducing the weight of the vehicle resulting in increased miles per gallon, faster acceleration and better handling and drivability.

Material construction of the engine should tolerate the higher temperatures associated with a high compression ratio and/or forced induction. An iron block engine can be suitable, but aluminum block engines might pose additional challenges.

Another example embodiment of the present invention provides for a Diesel fuel blend comprising of 90% conventional diesel fuel (75% saturated hydrocarbons, and 25% aromatic hydrocarbons) and 10% molecules of Formula II by volume. A CIICE using this blend to produce power will produce <50% particulate matter by mass than the same engine using conventional diesel. In addition, the CIICE using the 10% of molecules of Formula II (where R[sub]1 is an alkyl with between 1 and 8 carbon atoms) blend will have a prolonged life due to the lubricity properties of the blend.

Another example embodiment of the present invention provide for a fuel blend comprising of 100% of molecules from Formula II where R[sub]1 is an alkyl with between 1 and 12 carbon atoms which can then be burned as a standalone fuel or co-burned with coal to generate steam to power a steam turbine engine. Such a fuel can greatly reduce emissions of undesirable greenhouse gases while providing a clean, renewable, domestic fuel source.

Another example embodiment of the present invention provides for a fuel blend comprising of 15% of molecules of Formula II where R[sub]1 is an alkyl between 1 and 12 carbon atoms and 85% diesel in modern ships and boats. Such vessels are commonly powered by either two stroke or four stroke diesel (compression-ignition engine) engines. The advantages of using such a blend in marine vehicles include the ability to reduce the amount of crude oil in the blend by 15% and to increase lubricity which can improve performance and the life of both two stroke and four stroke compression-ignition engines.

Another example embodiment of the present invention provides for a fuel blend comprising of about 80% jet fuel such as jet-A, jet-A1, JP-8 or JP-5 by volume and about 20% molecules of Formula II where R[sub]1 is an alkyl with between 1 and 12 carbon atoms, by volume. In such a mixture, molecules of Formula II are used to displace crude oil products but also to reduce particulate matter emissions. In addition to environmental benefits, the high smoke point of molecules of Formula II can serve to reduce the soot trail of military aircraft. Another advantage of molecules of Formula II, especially those where R[sub]1 is an alkyl with between 3 and 12 carbon atoms, is the high energy density and low density of the final fuel blend. Another advantage is the increased lubricity of molecules of Formula II reduces wear on mechanical components of the jet itself, increasing the service life and reducing the chance of catastrophic equipment failure in between service intervals. In some embodiments, the present invention can also lower the freezing point of the fuel.

Another example embodiment of the present invention provides for a fuel blend comprising of 70% gasoline by volume and 30% molecules of Formula II where R[sub]1 is an alkyl with between 1 and 4 carbon atoms for use by two stroke engines. Due to the high lubricity of molecules in Formula II, the need for adding lubricating oil to the fuel mixture is eliminated. Two-stroke engines often provide high power-to-weight ratio, usually in a narrow range of rotational speeds called the “power band,” and, compared to 4-stroke engines, have a greatly reduced number of moving parts, are more compact, significantly lighter, and less costly to produce in comparison to four stroke engines. Because of the advantages of two stroke engines, they were very popular in the United States until the EPA mandated more stringent emission controls in 1978 (taking effect in 1980) and in 2004 (taking effect in 2005 and 2010). These engines are still very popular around the world. The example embodiment provided here can influence a resurgence in the use of two-stroke engines resulting in lower cost, more efficient two stroke engines that produce much less air pollution.

Another example embodiment of the present invention provides for a fuel blend comprising charcoal and molecules of Formula II where R[sub]1 is an alkyl with between 1 and 18 carbon atoms for use as a clean burning cooking fuel. Approximately 2.6 billion people throughout the world are in need of a clean burning cooking fuel. Cooking fuels currently in use such as coal, kerosene, or biomass produce toxic carbon monoxide gas during the combustion process and, in the case of kerosene, present fire hazards due to the high flammability of kerosene. In this example embodiment, molecules of Formula II can be utilized in place of these fuels to reduce indoor air pollution as well as reduce fire hazards for people currently using liquid or solid fuels for cooking.

Fuels and fuel additives according to the present invention can improve antiknock properties of leaded or unleaded gasoline. Fuels and fuel additives according to the present invention can lower the vapor pressure of leaded or unleaded gasoline. Fuels and fuel additives according to the present invention can reduce the toxicity of leaded or unleaded gasoline or diesel. Fuels and fuel additives according to the present invention can improve the fuel efficiency in spark ignition engines. Fuels and fuel additives according to the present invention can reduce harmful exhaust gas emissions as well as evaporative emissions in spark ignition engines. Fuels and fuel additives according to the present invention can reduce phase separation in leaded or unleaded gasoline that contains alcohol or other hygroscopic compounds. Fuels and fuel additives according to the present invention can reduce harmful exhaust gas emissions in compression ignition engines. Fuels and fuel additives according to the present invention can lower the cloud point and pour point in diesel fuels. Fuels and fuel additives according to the present invention can increase the lubricity of diesel fuels. Fuels and fuel additives according to the present invention can lower the freezing point of jet fuels. Fuels and fuel additives according to the present invention can increase the lubricity of jet fuels. Fuels and fuel additives according to the present invention can improve the fire safety of flammable or combustible liquids by increasing the flash point. Embodiments of the present invention provide liquid fuel compositions, which can be used as fuels, or as additives to fuels, or constituents of fuel mixtures.

The present invention has been described in connection with various example embodiments. It will be understood that the above description is merely illustrative of the applications of the principles of the present invention, the scope of which is to be determined by the claims viewed in light of the specification. Other variants and modifications of the invention will be apparent to those skilled in the art. 

We claim:
 1. A liquid fuel composition comprising of a major proportion of hydrocarbon liquid fuel base and a minor proportion of at least one molecule of formula I where R is hydrogen, alkyl, or aromatic, with between 1 to 10 carbon atoms, or combination of carbon, hydrogen, and oxygen and R[sub]1 comprises alkyl or aromatic, with between 1 to 18 carbon atoms, or a combination of carbon, hydrogen, nitrogen, and oxygen.
 2. A liquid fuel composition as in claim 1, wherein the at least one molecule of formula I comprises one or more of: an ester of 5-methyl-2-furoic acid, an amide of 5-methyl-2-furoic acid, and a thioester of 5-methyl-2-furoic acid, from a precursor consisting of 5-methyl-furaldehyde with one hydrogen of the 5-methyl group replaced with one of chloride, fluoride, bromide, iodide, p-toluenesulfonate, methanesulfonate, trifluoroacetate, phenoxy, hydroxy, or ammonium.
 3. A liquid fuel composition as in claim 1, wherein R is a methyl.
 4. A liquid fuel composition as in claim 1 further comprising jet fuel.
 5. A liquid fuel composition as in claim 4, wherein jet fuel comprises between 0.01% and 1% by volume of the composition.
 6. A liquid fuel composition as in claim 4, wherein molecules of Formula I comprise up to 20% by volume of the composition.
 7. A liquid fuel composition as in claim 1 further comprising gasoline.
 8. A liquid fuel composition as in claim 7, wherein gasoline comprises between 0.01% and 1% by volume of the composition.
 9. A liquid fuel composition as in claim 7, wherein molecules of formula I comprise up to 25% by volume of the mixture.
 10. A liquid fuel composition as in claim 1 further comprising diesel fuel.
 11. A liquid fuel composition as in claim 10, wherein diesel comprises between 0.01% and 1% by volume of the composition.
 12. A liquid fuel composition as in claim 10, wherein molecules of formula I comprise up to 30% by volume of the mixture.
 13. A liquid fuel composition as in claim 1, wherein the at least one molecule of formula I comprises a molecule of Formula II where R[sub]1 comprises an alkyl with between 1 to 12 carbon atoms.
 14. A liquid fuel composition as in claim 13, wherein least one molecule of formula I comprises an ester of 5-methyl-2-furoic acid having an alkoxycarbonyl portion, and wherein the alkoxycarbonyl portion is linear or branched aliphatic chain or a cyclic aliphatic, having at least 1 and not more than 20 carbon atoms.
 15. A liquid fuel composition as in claim 13, wherein least one molecule of formula I comprises an ester of 5-methyl-2-furoic acid having an aryloxycarbonyl portion, and wherein the aryloxycarbonyl portion is an aromatic ring, having at least 5 and not more than 10 carbon atoms.
 16. A liquid fuel composition as in claim 13, further comprising jet fuel.
 17. A liquid fuel composition as in claim 13, further comprising gasoline.
 18. A liquid fuel composition as in claim 13, further comprising diesel fuel. 